<%-- Created by IntelliJ IDEA. --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
  <head>
    <title></title>
  </head>
  <body>
demo的index.jsp
<%=application.getAttribute("yudushu")%>
  <form action="/demo/hello" method="post">
    <input type="text" name="account" value="haha">
    <input type="password" name="password" value="123">
    <button>提交</button>
  </form>
  </body>
</html>